Suppose that the septic inspection shows that the denial field is too small and does not comply with the rules in force. The buyer would object and require the seller to correct it at its own expense prior to conclusion. If the seller accepts or negotiates a payment agreement, it is a modification of the contract, even if it is not called a “modification”. Other frequently used add-ons are disclosure forms and specific inspection requirements. In New Mexico, for example, the Septic Inspection Addendum accompanied every contract for a home with a septic system. There was also a disclosure from the state to the buyer about the septic systems, which were also included separately. After guaranteeing the satisfaction of the other party, it is time to officially sign the agreement. The same parties who signed the original agreement are those who must also sign the addendum.